The fusion power plant design is facing several challenges that have to be overcome before it can start electricity production.
This paper presents a preliminary evaluation of the materials challenges presented by the conceptual design [1] for a Fusion Nuclear Science Facility (FNSF) to
“In order for the nuclei to fuse together on Earth, we need temperatures 10 times hotter than the Sun – around 100 million Celsius." UK Atomic
The fundamental challenges are the environment that fusion must occur in: nearly unimaginable heat & pressure. The Sun achieves this because
Illustrated cross section of a traditional doughnut-shaped tokamak fusion reactor. Tokamaks, such as the International Thermonuclear Experimental Reactor (ITER) in France, use electromagnetic fields to confine plasma and heat it to the temperatures and densities necessary to ignite fusion. Illustrated cutaway of a traditional doughnut-shaped tokamak fusion reactor. Illustrated cutaway of a traditional doughnut-shaped tokamak fusion reactor. Illustrated cutaway of the tokamak fusion reactor with particles spinning around the central solenoid. Illustrated cutaway of the tokamak fusion reactor with plasma spinning around the central solenoid. *5* • As the temperature rises, the density and energy within the plasma increase, causing particles to collide and initiate fusion. Illustrated cutaway of the tokamak fusion reactor with plasma spinning around the central solenoid. Illustrated cross section of a tokamak fusion reactor with plasma circulating around the central solenoid. All tokamaks confine the plasma using a central electric current that can make fusion reactions difficult to maintain**.
[Skip to Content](https://kleinmanenergy.upenn.edu/research/publications/bringing-fusion-energy-to-the-grid-challenges-and-pathways/#content). [Download PDF](https://kleinmanenergy.upenn.edu/wp-content/uploads/2025/10/KC-Digest-81-Bringing-Fusion-Energy-to-the-Grid.pdf). ](https://kleinmanenergy.upenn.edu/wp-content/plugins/a3-lazy-load/assets/images/lazy_placeholder.gif)](https://kleinmanenergy.upenn.edu/wp-content/uploads/2025/09/Fig-3.jpg)[](https://kleinmanenergy.upenn.edu/wp-content/uploads/2025/10/Fig-4.jpg). This category has over $2.5 billion in funding and 15 startups, such as TAE Technologies, Helion, and General Fusion.](https://kleinmanenergy.upenn.edu/wp-content/plugins/a3-lazy-load/assets/images/lazy_placeholder.gif)](https://kleinmanenergy.upenn.edu/wp-content/uploads/2025/10/Table-1-4.jpg). Historically, facilities like the [UR-LLE National Laser Users’ Facility](https://www.lle.rochester.edu/about-the-laboratory-for-laser-energetics/nluf/) (NLUF) program, the [DIII-D National Fusion Facility](https://science.osti.gov/fes/Facilities/User-Facilities/DIII-D), and Princeton’s [National Spherical Torus Experiment](https://science.osti.gov/fes/Facilities/User-Facilities/NSTX-U) have enabled hundreds of users to conduct experiments not possible at their home institutions, diffusing knowledge while harnessing national scientific ingenuity (U.S. Department of Energy 2024). “Promoting Fusion Energy Leadership with U.S. Tritium Production Capacity.” [_https://fas.org/publication/fusion-energy-leadership-tritium-capacity/_](https://fas.org/publication/fusion-energy-leadership-tritium-capacity/). “Major Funding Milestone for World-First Prototype Fusion Plant.” [_https://www.gov.uk/government/news/25-billion-for-world-first-prototype-fusion-energy-plant_](https://www.gov.uk/government/news/25-billion-for-world-first-prototype-fusion-energy-plant). “U.S. Department of Energy Announces Selectees for $107 Million Fusion Innovation Research Engine Collaboratives, and Progress in Milestone Program Inspired by NASA.” _[https://www.energy.gov/articles/us-department-energy-announces-selectees-107-million-fusion-innovation-research-engine](https://www.energy.gov/articles/us-department-energy-announces-selectees-107-million-fusion-innovation-research-engine)_. [More…](https://kleinmanenergy.upenn.edu/research/publications/bringing-fusion-energy-to-the-grid-challenges-and-pathways/#addtoany "Show all").
The sun, along with all other stars, is powered by a reaction called nuclear fusion. Today, we know that the sun, along with all other stars, is powered by a reaction called nuclear fusion. The amount of energy produced from fusion is very large — four times as much as nuclear fission reactions — and fusion reactions can be the basis of future fusion power reactors. On earth, we need temperatures exceeding 100 million degrees Celsius and intense pressure to make deuterium and tritium fuse, and sufficient confinement to hold the plasma and maintain the fusion reaction long enough for a net power gain, i.e. the ratio of the fusion power produced to the power used to heat the plasma. At the second United Nations International Conference on the Peaceful Uses of Atomic Energy, held in 1958 in Geneva, Switzerland, scientists unveiled nuclear fusion research to the world. The first international IAEA Fusion Energy Conference was held in 1961 and, since 1974, the IAEA convenes a conference every two years to foster discussion on developments and achievements in the field.
This paper emphasizes the critical need to test materials in their full-size component form and in the complete fusion environment of a fusion core.